Pluggable Databases - Expert Consolidation in Oracle Database 12c - page 265

You can query both to get more information about the plans defined in the CDB. After the creation of the
swingbench plan, I had the following contents in the DBA_CDB_RSRC_PLANS view:
SYS@CDB$ROOT> select plan,comments,status
2 from DBA_CDB_RSRC_PLANS;
PLAN COMMENTS STATUS
------------------------------ ------------------------------ ----------
DEFAULT_CDB_PLAN Default CDB plan
DEFAULT_MAINTENANCE_PLAN Default CDB maintenance plan
SWINGBENCH_PLAN
ORA$QOS_CDB_PLAN QOS CDB plan
ORA$INTERNAL_CDB_PLAN Internal CDB plan
The plan directives used previously are exported in the DBA_CDB_RSRC_PLAN_DIRECTIVES view:
SYS@CDB$ROOT> select pluggable_database, shares, utilization_limit,
2 parallel_server_limit
3 from DBA_CDB_RSRC_PLAN_DIRECTIVES
4 where plan = 'SWINGBENCH_PLAN'
5 order by PLUGGABLE_DATABASE;
PLUGGABLE_DATABASE SHARES UTILIZATION_LIMIT PARALLEL_SERVER_LIMIT
------------------------- ---------- ----------------- ---------------------
ORA$AUTOTASK 90 100
ORA$DEFAULT_PDB_DIRECTIVE 1 100 100
SWINGBENCH1 4 0
SWINGBENCH2 2 0
SWINGBENCH3 2 0
You will undoubtedly have noticed the ORA$AUTOTASK and default PDB directive in addition to the explicitly
created directives. These two—which are not explicitly covered in detail in this chapter—allow you to grant new
PDBs a different default weight in the case of the ORA$DEFAULT_PDB_DIRECTIVE. You change it using the
update_cdb_default_directive() function in DBMS_RESOURCE_MANAGER. As you already know, Oracle introduced
certain automatic maintenance tasks with 11g Release 1. Since these are also under control of the resource manager
they adhere to the same limits. If you'd like to change the priority of the automatic maintenance tasks then you can
change the ORA$AUTOTASK directive if you like.
Resource Manager for the Pluggable Database
The DBRM within the PDB is similar to how it used to before Oracle 12.1. Again, it allows the administrator to arrange
computing resources for resource consumer groups in the form of mapping of users to plan directives, all wrapped
up in resource plans. You can easily expand on the above example, which instructed the Oracle kernel to arrange the
available resources between PDBs. Once the individual PDB has received its resource quantum, it is up to the DBRM
to decide which users should have priority treatment.
There are some restrictions in the current release of the software, which you need to be aware of. The first
restriction is related to sub-plans. The plan_or_subplan argument to the create_plan_directive() function in
DBMS_RESOURCE_MANGER allows you to specify a subplan instead of a resource consumer group. The result
is a nested resource plan that can be difficult to understand or debug. With the current release you cannot assign
subplans. The number of consumer groups is restricted to a maximum of eight.
To enable a resource plan for a PDB, there has to be a resource plan in use in the CDB. This is a similar
requirement to Instance Caging (see next section), which also requires a Database Resource Plan to be present.